The Clinical Core will define the neuropsychological and neurological attributes of the two patient populations enrolled in the Boston University Alzheimer's Disease Research Center (BU ADCC). The Bedford VA Medical Center is a source of institutionalized patients with late stage Alzheimer's disease (AD) and ambulatory patients with earlier stages of dementia. Unlike the typical Alzheimer clinic in an acute hospital setting, patients are not lost to follow up and close contact is maintained with caregivers throughout all stages of the disease. This close relationship is a patient/family and provider partnership that has facilitated the recruitment of patients and caregivers into several research projects and has sustained an autopsy rate of 75% over the past 6 years. This exemplary standard of care and research will be applied to characterize the racially, ethnically and culturally diverse poor urban population served by the Boston University Home Medical Service (HMS). In contrast to the population served at the Bedford VA Medical Center, which is homogenous and middle class, about 40% of HMS patients are not caucasian, 60% are on Medicaid and 72% are female. All HMS patients receive a complete medical evaluation which will be reviewed to identify early stage or presymptomatic patients for enrollment in the clinical core. Enrolled subjects at the Bedford VA and the HMS will undergo a standardized, validated one hour neuropsychological evaluation every 6 months and an annual neurological evaluation and blood drawing. DNA will be extracted and stored and Apo E genotype will be determined. In selected cases, lymphoblastic cell lines will be created. All data collected will be entered into a standardized database. In conjunction with a major aim of the Education Core, patients and control subjects will be encouraged to donate their brains for research purposes. Family caregivers will be enrolled and a standardized assessment of caregiver burden will be performed annually. This database will provide a foundation for future research on interventions to reduce caregiver burden and studies concerning the emotional and financial impact of AD.